Collect Legal-Grade iPhone Evidence

I recently replaced my iPhone and opened a fresh iCloud account, yet the same intrusions continue: apps opening on their own, unexplained data spikes, unfamiliar devices popping up in the Apple-ID panel, and signs that someone may even be dropping custom OS files onto the handset... (Budget: $30 - $250 USD, Jobs: Data Analysis, Digital Forensics, Incident Response, iOS Development, iPhone, Legal, Legal Research, Mobile App Development)